I have a problem that when I use Waze with Android Auto, after the voice prompt tells me where to turn, the radio volume defaults back to 8 and I can't get it to default any higher. How do you set the radio default volume?

I figured out how to change the prompt volume default but not the regular radio volume default.

 

I would make sure your apps are up to date on your phone, then power cycle your phone, and check. If not, I'd erase phone from truck and reinstall